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2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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What’s the most difficult question you’ve been asked as a maintenance instructor?
Blye Widmar
"Where are the prints?!"
This was the final question in an onslaught of verbal feedback, comments, and critiques I received from my students back in 2019. I had two years of instructor experience and was teaching a class that had been meticulously rehearsed in preparation for an accreditation visit. I knew the training material well and transferred that knowledge effectively enough for all the students to pass the class. As we wrapped up, I asked the students how they felt about my first big system-level class, and they did not hold back.
“Why was the exam from memory when we don’t work from memory in the plant?” “Why didn’t we refer to the vendor documents?” “Why didn’t we practice more on the mock-up?” And so on.
Felix C. Difilippo
Nuclear Science and Engineering | Volume 142 | Number 2 | October 2002 | Pages 140-149
Technical Paper | doi.org/10.13182/NSE02-A2294
Articles are hosted by Taylor and Francis Online.
The analysis of the fluctuations of signals coming from detectors in the vicinity of a subcritical assembly of fissile materials is commonly used for the control and safeguard of nuclear materials and might be used for the surveillance of an accelerator driven system. One of the stochastic techniques is the measurement of the probability distributions of counts in time intervals t (gates); the departure of the ratio of the variance and the mean value with respect to 1 (the correlation) is directly related to the amount of fissile material and its subcriticality. The measurement of this correlation is affected by dead-time effects due to count losses because of the finite-time resolution of the detection system. We present a theory that allows (a) the calculation of the probability of losing n counts (P(n)) in gate t, (b) the definition of experimental conditions under which P(2) << P(1), and (c) a methodology to correct the measured correlation because of losing one count in any gate. The theory is applied to the analysis of experiments performed in a highly enriched subcritical assembly.
